[Bug nptl/20263] robust mutex deadlocks if other thread requests timedlock (Only arm/linux)

["t2wish at gmail dot com" <sourceware-bugzilla at sourceware dot org>]

https://sourceware.org/bugzilla/show_bug.cgi?id=20263

--- Comment #5 from Jiyoung Yun <t2wish at gmail dot com> ---
Thanks Florian Weimer!

When I fixed some code, my simple test is working properly. Please see the
below code. (Unfortunately in my office I can't clone the glibc repo...)

index 3a2725c..3c54ddd 100644
--- a/nptl/lowlevelrobustlock.c
+++ b/nptl/lowlevelrobustlock.c
@@ -113,15 +113,20 @@ __lll_robust_timedlock_wait (int *futex, const struct
timespec *abstime,
          && atomic_compare_and_exchange_bool_acq (futex, newval, oldval))
        continue;

+      int err;
       /* If *futex == 2, wait until woken or timeout.  */
 #if (!defined __ASSUME_FUTEX_CLOCK_REALTIME \
      || !defined lll_futex_timed_wait_bitset)
-      lll_futex_timed_wait (futex, newval, &rt, private);
+      err = lll_futex_timed_wait (futex, newval, &rt, private);
 #else
-      lll_futex_timed_wait_bitset (futex, newval, abstime,
+      err = lll_futex_timed_wait_bitset (futex, newval, abstime,
                                   FUTEX_CLOCK_REALTIME, private);
 #endif

+      /* the futex call time out */
+      if (err == -ETIMEDOUT)
+           return ETIMEDOUT;
+
     try:
       ;
     }


pthread_cond_Timedout
pthread_rwlock_timedrdlock
pthread_rwlock_timedwrlock
These codes are already handled the same situation. But in this case(robust
mutex) it doesn't. The lll_futex_timed_wait_bitset function was already
returned the -ETIMEDOUT but we skipped it. And it makes a daedlock.

-- 
You are receiving this mail because:
You are on the CC list for the bug.